Erinacine

Erinacines are natural substances isolated from the mycelium of Hericium erinaceus (lion's mane mushroom). They belong to the group of cyathin diterpenoids (erinacines A–K, P, Q, S, U) and are subjects of pharmacological research, which largely focuses on the benefits of erinacine on the brain.^[1] All erinacines are able to readily cross the blood–brain barrier in vivo, which largely influences the bioavailability of the compounds in the brain.

Chemical structures of erinacines A–I

Erinacine A

Erinacine A, isolated from the cultured mycelia of Hericium erinaceus, the main representative of this compounds group, has an enhancing effect on nerve growth factor synthesis in vitro.^[2] It also increases the levels of catecholamines in the central nervous system of rats.^{[citation needed]}. Erinacine A has been observed to lead to the activation of antioxidant pathways including the transcription factor Nrf2.^[1]

Erinacine A has also been prepared by total synthesis.^[3]

Erinacine C

Erinacine C has also been observed to activate the transcription factor Nrf2 and has been observed to play a role in neurogenesis and neuroplasticity.^[1]

Erinacine E

Erinacine E is a kappa opioid receptor agonist.^[4]

Erinacine S

Erinacine S has been shown to reduce neuropathic pain in vivo ^[5] and can increase myelination in vivo.^[6]